Role of marination, natural antimicrobial compounds, and packaging on microbiota during storage of chicken tawook

The aim of this study was to investigate the antimicrobial effect of marination, natural antimicrobials, and packaging on the microbial population of chicken tawook during storage at 4°C. Chicken meat was cut into 10 g cubes and marinated. The chicken was then mixed individually with 0.5% or 1% (w/v) vanillin (VA), β-resorcylic acid (BR), or eugenol (EU), and stored under aerobic (AP) or vacuum (VP) packing at 4°C for 7 d. The marinade decreased microbial growth as monitored by total plate count, yeast and mold, lactic acid bacteria, and Pseudomonas spp. by about 1 log cfu/g under AP. The combination of marinade and antimicrobials under AP and VP decreased growth of spoilage-causing microorganisms by 1.5 to 4.8 and 2.3 to 4.6 log cfu/g, respectively. Change in pH in VP meat was less than 0.5 in all treated samples including the control. Marination decreased the lightness of the meat (L*) and significantly (p < 0.05) increased the redness (A*) and yellowness (B*). Overall acceptability was highest for marinated samples with 0.5% BR.

Preservative effect of pomegranate-based marination with β-resorcylic acid and cinnamaldehyde on the microbial quality of chicken liver

Chicken liver is considered a delicacy in the Middle East where pomegranate molass is commonly used as a salad dressing and in marinade recipes. Marinated chicken liver is a common entrée and represents a value-added product compared to the otherwise unmarinated liver which commands a lower price. The aim of this study was to investigate the inhibitory effects of a pomegranate-based marinade alone or following the addition of cinnamaldehyde or β-resorcylic acid on the spoilage microorganisms present in chicken liver during storage for 14 d at 4°C or under mild temperature abuse conditions (10°C). The pH and microbial populations of total plate count (TPC), lactic acid bacteria (LAB), Pseudomonas spp. (PS), yeast and mold (YM), and Enterobacteriaceae (EN) were tested during the storage period and the shelf life was determined (defined as 107 log cfu/g). Sensory analysis was also conducted. The pH increased by a greater extent in unmarinated samples as compared to marinated samples (with or without antimicrobials) upon storage. The initial TPC, LAB, PS, YM, and EN microbial populations in the chicken liver were 3.85 ± 0.79, 3.73 ± 0.85, 3.85 ± 0.79, 3.73 ± 0.87, and 3.69 ± 0.23 log cfu/g, respectively. The marinade decreased the microbial populations by 2 to 4 log cfu/g. The marinade and antimicrobial mixture decreased the microbial populations by 3 to 4 log cfu/g. Except for 1 sample, none of the marinated chicken liver samples with or without antimicrobials reached the end of shelf life even up to 14 d of storage at both 4°C and 10°C. The overall sensory score was rated around 6/9 for the treated samples.

A worldwide review of illness outbreaks involving mixed salads/dressings and factors influencing product safety and shelf life

The trends toward healthy living, vegetarianism, and busy schedules have increased salad popularity. Salads are usually consumed raw without any thermal treatment, and therefore, without proper care they can become major vehicles for foodborne illness outbreaks. This review examines the microbial quality of 'dressed' salads which contain two or more vegetables/fruits and salad dressings. The possible sources of ingredient contamination, recorded illnesses/outbreaks, and overall microbial quality observed worldwide, besides the antimicrobial treatments available are discussed in detail. Noroviruses were most frequently implicated in outbreaks. Salad dressings usually play a positive role in influencing microbial quality. However, this depends on several factors like the type of contaminating microorganism, storage temperature, dressing pH and ingredients, plus the type of salad vegetable. Very limited literature exists on antimicrobial treatments that can be used successfully with salad dressings and 'dressed' salads. The challenge with antimicrobial treatments is to find ones sufficiently broad in spectrum, compatible with produce flavour which can be applied at competitive cost. It is evident that renewed emphasis on prevention of produce contamination at the producer, processor, wholesale and retail levels plus enhanced hygiene vigilance at foodservice will have a major impact on reducing the risk of foodborne illnesses from salads.

Occurrence of aflatoxins in nuts and peanut butter imported to UAE

Nuts are an important food group that contributes to maintaining health; however, they can be a source of exposure to aflatoxins. This study was conducted from 2017 to 2021 to assess the incidence of aflatoxins in nuts and nut products imported to the UAE from 57 countries. Associations between container type and processing technique and aflatoxin levels were also analyzed. A total of 5401 samples of pistachios, peanuts, peanut butter, and mixed nuts were examined using HPLC-FLD analysis in conjunction with immunoaffinity cleanup. In nuts, non-conformity was detected in samples imported from 32 different countries. Mean aflatoxin values for the non-compliant samples ranged from 81.0 to 92.7 μg/kg in pistachios, peanuts, and mixed nuts. A significant difference (p < 0.05) was found between mean aflatoxin levels in samples of peanut butter (29.3 μg/kg) compared to the other types of nuts. Nuts packed in containers made of fabric material had the highest mean aflatoxin levels of 108.1 μg/kg, while 29.7 μg/kg was the lowest mean level and was detected in nuts packed in glass. Ground samples had the highest aflatoxin levels (158.9 μg/kg) among processed products. This report will be valuable as a reference document in developing approaches to control nut importation and for establishing procedures that prevent food safety risks due to aflatoxin exposure. A need was underlined for the regulating authority to audit companies importing nuts, ensure safe practices are in place, and establish standards to minimize contamination and prevent the need for product rejection at the border.

Effect of Eugenol, Vanillin, and β-Resorcylic Acid on Foodborne Pathogen Survival in Marinated Camel Meat

The combined inhibitory effect of essential oils (EOs) with meat-based marinades has not been fully studied. Therefore, the present study aimed to gauge the effect of a yogurt-based marinade when individually combined with three EOs, namely eugenol (EU), vanillin (VA), or β-resorcylic acid (BR) on camel meat cubes inoculated with Listeria monocytogenes, Salmonella spp., and Escherichia coli O157:H7 during storage. Fresh camel meat cubes of 10 g were inoculated with bacteria and dipped in the mixture of marinade and EO. Overall, the study had six EO treatments (EU 0.5%, EU 1%, VA 0.5%, VA 1%, BR 0.5%, and BR 1%) and two controls (meat without marinade and marinated meat). Treated meat cubes were stored at 4°C or 10°C for 1, 4, and 7 d. Adding only marinade to the camel meat at 10°C decreased the pathogens by 0.8-2.4 log CFU/g. At 10°C, BR decreased L. monocytogenes, E. coli O157:H7, and Salmonella spp. by 2.0, 1.5, and 1.3 log CFU/g, while EU caused a decrease (p < 0.05) of 1.9, 1.2, and 0.9 log CFU/g, respectively. Similarly, VA caused a reduction in these microorganisms of 1.3, 1.1, and 1.0 log CFU/g, respectively (p < 0.05). The combination of marinade and EO resulted in a decrease of the pathogens ranging from 0.9-1.4 and 2.8-3.7 log CFU/g at 4 and 10°C, respectively. The antimicrobial efficacy of EO alone or when combined with marinade was higher at 10°C than at 4°C with all three pathogens at both 0.5% and 1%. Overall, EOs were found to enhance the microbial safety of camel meat. In addition, they are antimicrobials that occur naturally, require a minimum investment, and may prove to be a great asset for marinated camel meat producers.

Inhibition of spoilage bacteria on marinated chicken by essential oils under aerobic and vacuum packaging

"Chicken tawook" is a marinated boneless chicken entrée consumed in the Middle East. The aim of this study was to determine whether bioactive essential oil (EO) components carvacrol (CA), cinnamaldehyde (CI), and thymol (TH) would delay the growth of microorganisms causing tawook spoilage during aerobic (AP) or vacuum (VP) packed storage. The EOs at 1% and 2% were mixed individually with the marinade. The samples (10 g of chicken cubes with 1.2 g of marinade - with or without EOs) were stored in bags under AP and VP (Geryon^® ) for 7 days at 4 ± 1°C and abusive conditions (10 ± 1°C). Two control samples consisting of meat chunks and tawook without EO were used. The microflora numbers were greater at 10°C than at 4°C, and the marinade worked additively with AP against anaerobes, yeast and mold (Y & M) and lactic acid bacteria. It also worked additively with VP against aerobic bacteria recovered as Pseudomonas and the total plate count. EO components were observed to decrease microbial populations by a maximum of 4 to 6 log colony-forming unit (CFU)/g depending on the type of microorganism. The combined mixture of marinade and 2% EO (CA, CI, and TH) resulted in the greatest reductions of all spoilage microorganisms at 10°C under AP on the last day of storage. Overall, VP was more effective (p < 0.05) than AP in controlling microorganisms at both 4 and 10°C. This study provides an affordable and natural alternative for extending product life. PRACTICAL APPLICATION: The use of EOs in marinated chicken (tawook) is expected to help producers reduce spoilage and extend shelf-life of the product when stored at refrigeration temperatures. EOs provide a cheaper alternative and are naturally sourced. Vacuum packaging will increase the shelf-life of marinated chicken tawook and facilitate its storage and transportation.

Consumers' knowledge and attitudes about food additives in the UAE

The use of food additives (FAs) in food manufacturing is a well-accepted practice worldwide. Inadequate knowledge concerning their safety may cause negative attitude surrounding their use. This would potentially impact the purchase of foods that the consumer perceives as containing FAs. This study aimed to assess knowledge and attitudes of consumers towards the use and safety of FAs in the UAE. A cross-sectional study was conducted using an online survey distributed via social media platforms (n = 1037). Less than one-third of the participants (26.7%) in this study stated that they knew what FAs are. About half the respondents believed that organic products did not contain FAs. The proportion of respondents who reported that the purpose of adding FAs is to extend shelf life, better the taste and aroma of food, enhance nutritional value, improve consistency and texture, and boost appearance and color was 92.1%, 75.0%, 23.5%, 56.6%, and 69.4%, respectively. Around 61% believed that all FAs were harmful to human health. The level of FA knowledge increased with age and education level. About 60% of the respondents reported that food labels did not provide sufficient information about FAs. The most preferred platforms for consumers to receive information about FAs were social media (41.1%), followed by brochures (24.6%). Overall, the UAE population had inadequate knowledge and a hesitant attitude concerning FAs. The municipalities and food industry should play an active role in educating the public to prevent and reduce any possible adverse attitudes towards processed food products.

In Vitro Characterization and Identification of Potential Probiotic Yeasts Isolated from Fermented Dairy and Non-Dairy Food Products

This study is about the isolation of yeast from fermented dairy and non-dairy products as well as the characterization of their survival in in vitro digestion conditions and tolerance to bile salts. Promising strains were selected to further investigate their probiotic properties, including cell surface properties (autoaggregation, hydrophobicity and coaggregation), physiological properties (adhesion to the HT-29 cell line and cholesterol lowering), antimicrobial activities, bile salt hydrolysis, exopolysaccharide (EPS) producing capability, heat resistance and resistance to six antibiotics. The selected yeast isolates demonstrated remarkable survivability in an acidic environment. The reduction caused by in vitro digestion conditions ranged from 0.7 to 2.1 Log₁₀. Bile salt tolerance increased with the extension in the incubation period, which ranged from 69.2% to 91.1% after 24 h. The ability of the 12 selected isolates to remove cholesterol varied from 41.6% to 96.5%, and all yeast strains exhibited a capability to hydrolyse screened bile salts. All the selected isolates exhibited heat resistance, hydrophobicity, strong coaggregation, autoaggregation after 24 h, robust antimicrobial activity and EPS production. The ability to adhere to the HT-29 cell line was within an average of 6.3 Log₁₀ CFU/mL after 2 h. Based on ITS/5.8S ribosomal DNA sequencing, 12 yeast isolates were identified as 1 strain for each Candidaalbicans and Saccharomyces cerevisiae and 10 strains for Pichia kudriavzevii.

Prevalence, Antibiotic-Resistance, and Growth Profile of Vibrio spp. Isolated From Fish and Shellfish in Subtropical-Arid Area

The study aimed to determine the prevalence of different species of Vibrio spp. in fish and shellfish sold in subtropical-arid countries (United Arab Emirates). It also examined the antimicrobial resistance of the isolated species and their growth behavior upon in vitro environmental changes concerning temperature, pH, and salinity. The prevalence of Vibrio spp. in fish and shellfish samples, was 64.5 and 92%, respectively. However, Vibrio parahemolyticus were detected in a mere 7.5 and 13.0% of the samples, respectively. On the other hand, Vibrio mimicus was detected in 1.5 and 8.5% of the samples, respectively. None of the six antibiotics studied except for Sulfamethoxazole-trimethoprim were effective against fish Vibrio spp. isolates. On a similar note, three antibiotics, namely Penicillin, Daptomycin, and Vancomycin, were ineffective against the shellfish isolates. The growth of the microorganisms did not show any significant trend with changes in pH and salinity. The optimum temperature for Vibrio spp. growth was observed to be 37°C.

Antimicrobial effects of chitosan and garlic against Salmonella spp., Escherichia coli O157:H7, and Listeria monocytogenes in hummus during storage at various temperatures

The study aimed to evaluate the antimicrobial activity of 0.5 or 1% (w/w) chitosan and 1% (w/w) garlic against Salmonella spp., Escherichia coli O157:H7 and Listeria monocytogenes in hummus dip stored at 4, 10, or 25°C for 28, 21, or 7 days, respectively. In hummus without garlic, at all storage temperatures and storage periods, 0.5% chitosan decreased Salmonella spp., E. coli O157:H7, and L. monocytogenes by 0.9-2.3, 0.6-2.3, and 0.9-1.3 log CFU/g, respectively. In comparison, 1% chitosan decreased the numbers by 1.6-2.9, 1.4-2.7, and 1.3-1.8 log CFU/g, respectively. In hummus with 1% garlic, 0.5% chitosan decreased Salmonella spp., E. coli O157:H7, and L. monocytogenes by 0.7-2.5, 0.6-2.2, and 1.0-1.5 log CFU/g, respectively. Furthermore, 1% chitosan decreased the numbers by 1.6-2.8, 1.2-2.7, and 1.5-1.6 log CFU/g, respectively. With few exceptions, adding 1% garlic to hummus did not result in any significant reduction (at p < 0.05) in microbial numbers. The greatest decreases of Salmonella spp., E. coli O157:H7, and L. monocytogenes were 3.1, 3.6, and 2.9 log CFU/g with 1% chitosan held at 4°C for 28 days. The highest overall acceptability was for hummus with 0.5% chitosan + 1% garlic. Commercial use of chitosan is expected to help producers improve hummus safety. PRACTICAL APPLICATION: Hummus is consumed worldwide as a dip due to its taste and health benefits. Microbial safety of hummus can be enhanced by incorporating chitosan, derived from the natural polymer chitin, into the formulation. This enhanced recipe would be a bonus for producers and consumers alike.

Impact of coronavirus 2019 on mental health and lifestyle adaptations of pregnant women in the United Arab Emirates: a cross-sectional study

Background

In light of the pandemic, pregnant women are particularly vulnerable to increased psychological distress and in need of imperative preventive measures. This study aimed to investigate the impact of the pandemic on mental health, lifestyle adaptations, and their determinants among pregnant women in the United Arab Emirates.

Methods

A survey was conducted electronically between June and August 2020. Pregnant women were recruited from prenatal clinics in the UAE and invited to participate in an online survey developed on Google Forms. The questionnaire included socio-demographic characteristics, the Impact of Event Scale- Revised, the Perceived Support Scale and lifestyle-related factors.

Results

A total of 384 pregnant women completed the questionnaire of whom 20.6% were in their 1st trimester, 46.1% in their 2nd and 33.3% in their 3rd trimester. The mean IES-R score for the respondents was 26.15 ± 13.55, corresponding to a mild stressful impact, which did not differ significantly among trimesters of pregnancy. Pregnant women expressed increased stress from staying home (64%), work (40%), feeling frightened (66%) and apprehensive (59%). Women reported increased support and sharing their feelings with family members (59%), mainly in the 1st and 3rd trimester of pregnancy (P < 0.05). There was a greater attention to mental health (48%), resting time (55.3%), and relaxing time (57.3%); while a decreased amount of time was spent engaging in physical activities (53.6%), which differed significantly between trimesters (P = 0.02).

Conclusions

The COVID-19 pandemic was associated with a mild stressful impact among pregnant women in the UAE, braced by strong family support and self-care mental health behaviors.

Effect of active essential oils added to chicken tawook on the behaviour of Listeria monocytogenes, Salmonella spp. and Escherichia coli O157:H7 during storage

The objective of the study was to assess the antimicrobial effect of active essential oil components (EOs) namely (carvacrol (CA), cinnamaldehyde (CI) and thymol (TH)) on Listeria monocytogenes, Salmonella spp., and Escherichia coli O157:H7 in chicken tawook during storage at 4 and 10 °C. A marinade consisting of ingredients commonly used in the chicken tawook recipe was prepared and mixed with 1% and 2% v/v CA, CI or TH. The marinade with or without EOs was added to fresh chicken breast cubes inoculated with the foodborne pathogens. Afterward, marinated chicken "tawook" was stored at 4 and 10 °C covered with cling wrap to mimic chill and mild abuse storage conditions for up to 7 days. At 10 °C, the marinade decreased L. monocytogenes numbers on day 4 and 7 by about 2.4 log₁₀ CFU/g as compared to unmarinated samples. Adding EOs to chicken tawook did not change L. monocytogenes numbers during storage at 4 and 10 °C. For Salmonella spp., the marinade decreased the numbers during 10 °C storage on day 4 and 7 by about 4.9 log₁₀ CFU/g as compared to unmarinated samples. At 4 °C, EOs at 2% decreased Salmonella spp. on day 7 by 0.5 log₁₀ CFU/g. One percent CI significantly decreased Salmonella by 1.5 log₁₀ CFU/g, at day 4 of storage. At 10 °C, 1% CA, 2% CI, 1% and 2% TH decreased Salmonella spp. in the samples by 0.5 log₁₀ CFU/g on day 7. The marinade decreased E. coli O157:H7 numbers on the chicken samples during 10 °C storage on day 4 and 7 by about 3.3 log₁₀ CFU/g as compared to unmarinated samples. Regardless of storage day at 4 °C, EOs decreased E. coli O157:H7 populations in chicken tawook by ≤2.4 log₁₀ CFU/g compared to samples without EOs, where the decrease was ≤1.4 log₁₀ CFU/g. Moreover, no significant decrease in E. coli O157:H7 populations could be attributed to the addition of EOs in samples which were stored at 10 °C. Increasing the concentration of EOs from 1 to 2% seemed to have no significant effect in reducing the tested foodborne pathogen populations.

Microbiological quality of kitchens sponges used in university student dormitories

Background

Kitchen sponges are a major source of cross-contamination as they can transfer foodborne pathogens, infectious agents and spoilage causing microorganisms to food contact surfaces. Several studies have revealed that university students adopt poor practices regarding food safety, hygiene, and the handling of kitchen cleaning equipment.

Methods

A total of fifty kitchen sponges were collected along with a questionnaire addressing social demographics and kitchen sponge usage by students living at the University of Sharjah dormitories. The effect of storage (3 and 10 days) on the microbial population of kitchen sponges at room temperature (21 °C) was assessed. Enterobacteriaceae isolated from sponges were identified and their antibiotic resistance determined.

Results

Student responses revealed that kitchen sponges used to clean food contact surfaces were also used to clean the oven (32%), sink (26%), refrigerator (10%), and to clean spills on the floor (4%). Kitchen sponges contained high counts of mesophilic aerobic bacteria (7.9 log₁₀/cm³), coliform (7.2 log₁₀/cm³), Enterobacteriaceae (7.3 log₁₀/cm³) and yeasts and molds (7.0 log₁₀/cm³). After storage of the sponges at room temperature (21 °C) for 3 and 10 days, the number of mesophilic aerobic bacteria, coliform, Enterobacteriaceae and yeasts and molds decreased by 0.4 and 1.3 log₁₀/cm³, 0.7 and 1.4 log₁₀/cm³, 0.4 and 1.1 log₁₀/cm³, and 0.6 and 1.3 log₁₀/cm³, respectively. The most frequently isolated Enterobacteriaceae were Enterobacter cloacae (56%) and Klebsiella oxytoca (16%). All E. cloacae isolates were resistant to amoxicillin, cefalotin, cefoxitin and cefuroxime axetil.

Conclusions

This study showed that students living in dormitories lacked good hygienic practices and were at increased risk of food poisoning. Kitchen sponges were highly contaminated with potentially pathogenic bacteria which could be transferred from the general kitchen environment to food contact surfaces and consequently lead to food contamination.

Microbial safety of oily, low water activity food products: A review

Oily, low water activity (OL a_w) products including tahini (sesame seed paste), halva (tahini halva), peanut butter, and chocolate, have been recently linked to numerous foodborne illness outbreaks and recalls. This review discusses the ingredients used and processing of OL a_w products with a view to provide greater understanding of the routes of their contamination with foodborne pathogens and factors influencing pathogen persistence in these foods. Adequate heat treatment during processing may eliminate bacterial pathogens from OL a_w foods; however, post-processing contamination commonly occurs. Once these products are contaminated, their high fat and sugar content can enhance pathogen survival for long periods. The physiological basis and survival mechanisms used by pathogens in these products are comprehensively discussed here. Foodborne outbreaks and recalls linked to OL a_w foods are summarized and it was observed that serotypes of Salmonella enterica were the predominant pathogens causing illnesses. Further, intervention strategies available to control foodborne pathogens such as thermal inactivation, use of natural antimicrobials, irradiation and hydrostatic pressure are assessed for their usefulness to achieve pathogen control and enhance the safety of OL a_w foods. Sanitation, hygienic design of manufacturing facilities, good hygienic practices, and environmental monitoring of OL a_w food industries were also discussed.

Updates on understanding of probiotic lactic acid bacteria responses to environmental stresses and highlights on proteomic analyses

Probiotics are defined as live microorganisms that improve the health of the host when administered in adequate quantities. Nonetheless, probiotics encounter extreme environmental conditions during food processing or along the gastrointestinal tract. This review discusses different environmental stresses that affect probiotics during food preparation, storage, and along the alimentary canal, including high temperature, low temperature, low and alkaline pH, oxidative stress, high hydrostatic pressure, osmotic pressure, and starvation. The understanding of how probiotics deal with environmental stress and thrive provides useful information to guide the selection of the strains with enhanced performance in specific situations, in food processing or during gastrointestinal transit. In most cases, multiple biological functions are affected upon exposure of the cell to environmental stress. Sensing of sublethal environmental stress can allow for adaptation processes to occur, which can include alterations in the expression of specific proteins.